Answer:
natural disasters,emigration and scarcity of food
Explanation: natural disasters: this affect population where by organisms leave there area or habitat for another area due to unfavorable conditions eg. flood, bush fire, storms, earthquake etc. and can also lead to death.
Emigration:this is when organisms leave an area for another either in search of food, breeding purpose this reduses population where by organisms may never return.
scarcity of food:this occur when there is insufficiency or no food in an area which makes organisms leave their habitat for another in search of food and might even lead to death.
Answer:
The answer is A, open systems!!
Explanation:
all systems on earth are open, except for the earth itself.
Well there alot of challenges faced by biologist researchers during the research of infectious disease, however major of those include the followings:
1- Defining and measuring the fitness for pathogens across the scales
2- Developing models to capture the impact of co-infection on the evolutionary process
3- Modeling how pathogen characteristics shape the evolution of hose immune diversity
4- Understanding the maintenance of pathogen diversity
5- Developing the better models for the impact of genetic systems on pathogen evolution .
All ecosystems contain biotic and abiotic parts, so answer d.
